Embodiments of the present invention generally relate to improvements in a medical imaging system, and more particularly relate to a compact bumper system used with a medical imaging system.
Various imaging modalities, such as MR, CT, ultrasound, x-ray, and PET, are used in diagnostic and/or surgical procedures. Typically, imaging systems include an imaging device proximate a patient positioning area, and a control and display unit, which is used to operate and control the imaging device. The imaging device may be a camera, x-ray detector/emitter, gamma camera, ultrasound transducer, or various other systems used to image a patient.
A patient to be imaged is positioned within the patient positioning area. For example, as shown in FIG. 5, the patient positioning area may include a support table 98 or chair to support and stabilize the patient. The imaging device, which may include a detector 110 and/or an emitter 114, may be configured to translate toward and away from the patient in an axial X direction and/or a radial R direction.
Many x-ray imaging systems include an x-ray source, a detector, and a positioning arm, such as a C-arm, supporting the x-ray source and the detector. In operation, an imaging table, on which a patient is positioned, is located between the x-ray source and the detector. The x-ray source typically emits a conical beam of radiation, such as x-rays, toward the patient. The conical beam has a theoretical central beam. The radiation typically passes through the patient positioned on the imaging table and impinges on the detector. As the radiation passes through the patient, anatomical structures of different densities inside the patient cause intensity variances in the radiation received at the detector. The detector then translates the radiation variances into an image that may be employed for clinical evaluations. Typically, the x-ray source is directly mounted to a distal end of the C-arm while the x-ray detector is mounted to another distal end of the C-arm. The x-ray source is positioned such that emitted x-rays are received by the x-ray detector.
The C-arm is mounted to the support structure, which may be mobile or fixed, through a bearing assembly. The bearing assembly allows the C-arm to rotate relative to the support structure. Therefore, anatomical structures of a patient positioned between the x-ray source and the x-ray detector may be imaged from different angles and perspectives. That is, the x-ray source and the x-ray detector rotate around the patient thereby imaging anatomical structures of the patient from various angles and perspectives.
During operation of an imaging system, it is often desirable to have the imaging device, such as an x-ray detector, as close as possible to the patient to improve the resolution and quality of the resulting images. With respect to x-ray imaging systems, placing the detector in close proximity to the patient helps to eliminate air gaps between the patient and the detector that may cause scattering of the x-rays. Further, as mentioned above, an imaging device may be moved relative to a patient thereby increasing the possibility of the imaging device colliding with the patient. For example, a C-arm of an imaging system is often rotated or maneuvered around a patient to obtain various imaging angles and perspectives. Therefore, with motorized mobile C-arms, there is a danger that the detector may contact or collide with the patient.
FIG. 3 illustrates a side view of a general imaging device 96. The imaging device 96 may be an x-ray detector, gamma camera, ultrasound transducer, or various other types of imaging devices that may be used with various imaging modalities. As shown in FIG. 3, collisions against the imaging device 96 may occur in the axial X, radial R, and diagonal D directions. In addition, collisions may occur when the detector rubs against the patient, thereby potentially causing harm to the patient.
In order to protect the patient from such collisions, some imaging systems include pads or protective bumpers. One such system uses a circular profile air (or fluid) bumper that is mounted around the outer wall of the detector. For example, FIG. 6 illustrates a cross sectional view of a center portion of a general imaging device 96 having a main body 92. The imaging device 96 includes a circular profile bumper 94 adjacent to, and encircling the main body 92. A circular profile, however, has some inherent disadvantages due to its geometry.
As the surface area of a bumper increases, the bumper's ability to distribute and absorb an impact force increases. A bumper having a circular profile has a low surface area to volume ratio. In order to provide an adequate level of load distribution, a circular bumper typically needs a relatively large diameter, which is a disadvantage because space is limited in various medical procedures.
Additionally, a circular or oblong profile constrains the size and use of the bumper. When a fluid filled bumper experiences an impact, the force of the impact causes a change in the internal pressure of the bumper. Typically, the size of the pressure fluctuation caused by an impact will increase as the volume of the bumper decreases. A smaller bumper, therefore, is more pressure sensitive to an impact force. Because an imaging device may be controlled in response to bumper pressure fluctuation measurements, a more pressure sensitive bumper may be preferred. Also, a circular (or oblong) profile limits protection along any one axis, either axially or radially, depending on the mounting position of the bumper.
Therefore a need exists for a minimally intrusive contact detection and impact load absorption system. A need also exists for a system that detects and absorbs contact/collisions in multiple directions, and that provides better load distribution and better pressure sensitivity.